Trivinylcyclohexanes are known and can be prepared by the thermal rearrangement of 1,5,9-cyclododecatriene (CDT). Wilke and coworkers in U.S. Pat. No. 3,011,003 and in Angew. Chem., 75 (1963) 27 disclose such a process, which comprises (1) heating CDT in the absence of a catalyst to a temperature between 300° C. and 650° C. thereby forming trivinylcyclohexane product, and (2) separating out the trivinylcyclohexane product by distillation. Although a broad reaction temperature range has been disclosed, according to the patentees, particularly suitable reaction temperatures are between 450° C. and 550° C. The reason is that the rearrangement proceeds considerably more slowly at lower temperatures and other lower molecular weight hydrocarbons, including butadiene, are formed at higher temperatures.
Trivinylcyclohexanes can also be prepared in the presence of a catalyst, typically a metal or a metal oxide. Examples of the catalysts are palladium, chromium oxide, iron oxides, and a wide range of mixed transition and/or main group metal oxides. Illustratively, U.S. Pat. No. 2,967,895 and GB 848637 disclose a process, which includes heating CDT at temperatures between 400° C. and 600° C. in the presence of a palladium catalyst. According to the patentees, no reaction takes place at lower temperatures and troublesome side reactions predominate at higher temperatures. Chromium oxide (Cr2O3), which contains smaller quantities of K2O, CaO, NiO and P2O5, on an Al2O3 support, has also been disclosed as a catalyst for preparing 1,2,4-trivinylcyclohexane, as for example, in SU 390058. The temperatures utilized in this process are from 350° C. to 500° C.
Unfortunately, these prior art processes typically have low selectivity and poor conversion rates and result in mixture of several stereoisomers. None of the prior art references disclose or suggest distinction among isomers, much less any processes to provide trivinylcyclohexane enriched in any particular isomer.
Accordingly, there is a need for a commercial and cost-effective process to produce 1,2,4-trivinylcyclohexane that is enriched in a desirable isomer and can be made in high yields and with high selectivity. The present invention provides an answer to that need.